Diamonds $1,000 to $2,500

This is the range where most engagement rings are actually bought, and it is where the single biggest decision on the whole site gets made: one carat mined, or two carats grown, for roughly the same money.

There is no correct answer, only two honest ones. The mined stone is scarce, it has a resale market, and it carries the history that a lot of people are buying in the first place. The grown stone is optically identical, visibly larger, and lets you take clarity and colour grades that the mined budget would not stretch to. Both are diamonds; only one of them is rare.

Whichever way that goes, the same rule applies at this budget: buy the cut. Between $1,000 and $2,500 there are enough well-proportioned stones in every shape that there is no reason to accept a Good cut to gain a tenth of a carat. And buy just under the round weights — 1.90ct rather than 2.00ct, 0.92ct rather than 1.00ct — because the price steps at the number while the millimetres barely move.

Compare them in 360° before deciding. It settles most arguments faster than the reports do.